Add optimization remarks for when prefetch targets cannot be mapped.

Author: rlavaee

llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp

@@ -2168,6 +2168,14 @@ void AsmPrinter::emitFunctionBody() {
     // If the block ends with a call, we may need to emit a prefetch target
     // at the end.
     EmitPrefetchTargetSymbolIfNeeded();
+    if (PrefetchTargetIt != PrefetchTargets.end()) {
+      MachineOptimizationRemarkMissed R(
+          "insert-code-prefetch", "MissingPrefetchTarget",
+          MF->getFunction().getSubprogram(), &MBB);
+      R << "failed to map "
+        << ore::NV("NumMissedTargets", PrefetchTargets.end() - PrefetchTargetIt)
+        << " prefetch targets";
+    }
 
     // We must emit temporary symbol for the end of this basic block, if either
     // we have BBLabels enabled or if this basic blocks marks the end of a

llvm/lib/CodeGen/BasicBlockSectionsProfileReader.cpp

@@ -93,7 +93,7 @@ uint64_t BasicBlockSectionsProfileReader::getEdgeCount(
   return EdgeIt->second;
 }
 
-SmallVector<BBPosition>
+SmallVector<SubblockID>
 BasicBlockSectionsProfileReader::getPrefetchTargetsForFunction(
     StringRef FuncName) const {
   return ProgramPathAndClusterInfo.lookup(getAliasName(FuncName))
@@ -332,7 +332,7 @@ Error BasicBlockSectionsProfileReader::ReadV1Profile() {
         return createProfileParseError(Twine("unsigned integer expected: '") +
                                        PrefetchTargetStr[1]);
       FI->second.PrefetchTargets.push_back(
-          BBPosition{*TargetBBID, static_cast<unsigned>(TargetCallsiteIndex)});
+          SubblockID{*TargetBBID, static_cast<unsigned>(TargetCallsiteIndex)});
       continue;
     }
     default:
@@ -541,7 +541,7 @@ uint64_t BasicBlockSectionsProfileReaderWrapperPass::getEdgeCount(
   return BBSPR.getEdgeCount(FuncName, SrcBBID, SinkBBID);
 }
 
-SmallVector<BBPosition>
+SmallVector<SubblockID>
 BasicBlockSectionsProfileReaderWrapperPass::getPrefetchTargetsForFunction(
     StringRef FuncName) const {
   return BBSPR.getPrefetchTargetsForFunction(FuncName);

llvm/lib/CodeGen/InsertCodePrefetch.cpp

@@ -70,12 +70,12 @@ bool InsertCodePrefetch::runOnMachineFunction(MachineFunction &MF) {
     return false;
   // Set each block's prefetch targets so AsmPrinter can emit a special symbol
   // there.
-  SmallVector<BBPosition> PrefetchTargets =
+  SmallVector<SubblockID> PrefetchTargets =
       getAnalysis<BasicBlockSectionsProfileReaderWrapperPass>()
           .getPrefetchTargetsForFunction(MF.getName());
   DenseMap<UniqueBBID, SmallVector<unsigned>> PrefetchTargetsByBBID;
   for (const auto &Target : PrefetchTargets)
-    PrefetchTargetsByBBID[Target.BBID].push_back(Target.CallsiteIndex);
+    PrefetchTargetsByBBID[Target.BBID].push_back(Target.SubblockIndex);
   for (auto &MBB : MF) {
     auto R = PrefetchTargetsByBBID.find(*MBB.getBBID());
     if (R == PrefetchTargetsByBBID.end())